A radiation curable resin that includes from 10 to 40 equivalent percent (based on the isocyanate groups) of the resin of an allophanate containing material having one or two allophanate groups; from 0 to 40 equivalent percent of the resin of an allophanate containing material having three or more allophanate groups; and from 60 to 90 percent by equivalent of the resin of urethane acrylates. The resin has an equivalent weight of ethylenically unsaturated groups capable of undergoing a polymerization reaction of from 0.001 to 0.008 eq./g. The resin is used in radiation curable coating compositions that also include one or more photoinitiators, and optionally one or more reactive diluents, and optionally a solvent or solvent mixture.